1. Field of the Invention
The invention relates to communications networks in general and more particularly to predicting stations which are likely to be failing.
2. Prior Art
Communications networks are facilities which allow users to exchange information. A typical communications network consists of a communication highway formed from a conductive media and a plurality of stations called nodes connected to said conductive media. A node may include copiers, computers, telephones, printers, etc. Such communications networks are in small geographical areas such as an office or in large geographical areas such as office buildings, college campuses and business establishments.
Because most communications networks are distributed over a finite geographical area, it is desirable to have a central location, with management facility, from which an operator monitors and manages the network.
The management facility would not only identify failed or failing devices but also predict when a communications network is going to fail. Thus, the operator would be given an opportunity to remove the failing device before it causes a catastrophic failure.
The monitoring and logging of errors in a machine or the like is well known in the prior art. Usually, if the machine is running satisfactorily, no action is taken. However, in the absence of satisfactory performance, an operator reviews a printout of an error log to identify probable sources of the error. Even though the post analysis technique works well for its intended purpose, it is unacceptable because it is available only after the machine is down. This type of failure is catastrophic and cannot be tolerated in today's environment where the availability of information is important to the orderly conduct of business.
U.S. Pat. No. 4,589,080 also provides what appears to be a pre-analysis technique for predicting failure in a copier. In this patent selected points in the copier are monitored by signal lines connected to the copier. If a signal is detected on a signal line, the time of occurrence is stored in the computer's memory at a location associated with the point that caused the signal. Eventually an array of the times of operation of each monitored point will be stored. The computer then calculates the difference between the times stored for selected pairs of the monitored points and stores these, as intervals, in additional locations of the memory. The intervals are combined to give calculated statistical results (mean, deviation, etc.) each of which is then compared against predetermined values normal for correctly operating copiers also stored in the memory. The results of the comparison set error flags if the limits are exceeded indicating possible future copier failures.
U.S. Pat. No. 4,339,657 describes a technique for error logging by integrating error counts over a selected number of operations and comparing the results with a criterion. An exception is logged if the number of errors exceeds the criterion, but the exception log is cleared if the number of errors is less than the criterion. However, the prior art does not provide apparatus and/or techniques for predicting failure in a communications network by analyzing error counts in messages generated and supplied to a central station from stations in the network.